WINSHIELD WIPER(PASSENGER SIDE ONLY

This morning when I tried to clean the winshield, the wash did not come out and only the driver side wiper worked. I recently filled up the winshield wash. Everything was workign fine a couple days ago. I was driving for about 45 mins in a snow storm on Monday and had the wipers going at full speed most of the time. I own a mercedes s550. I checked the wiper on the passenger side and it was not 'stuck' or unhitched. And the wiper wash was not clogged. Do you think the motor is busted? Is there a separate motor for the passenger and driver wiper? Thanks

Turns out, some part of the mechanism must have been frozen (was 15 degrees outside). Though neither worked during a 10 minute " warm-up" and a 45 minute drive to work, there was no problem that night when I left work, after the car had been in an indoor parking lot for 9 hours.